Transcript Navigation - Chapter 2: Compass

Flotilla 12-10
Navigation Study Guide
Chapter 6: Piloting
Instructor: Forrest Meiere
All Questions and Problems
from the Study Guide
PowerPoint Presentation
by Forrest Meiere
Flotilla 12-10
Navigation Study Guide
S6-l. What distinguishes PILOTING from other
branches of navigation? The reference to charted
landmarks, ATONs and depth soundings.
S6-2. Why are LOPs drawn on buoys (floating atons) to be
treated with caution? Buoys can be sunk or off station.
(Buoys can be moved and the new position may not be
on the chart being used.)
Flotilla 12-10
Navigation Study Guide
S6-3. What is the proper way to label an LOP?
On its top with the time of observation (24 hour system)
and on the bottom with the bearing from the vessel to
the object.
S6-4. How can a relative bearing be used to plot an LOP?
Add the relative bearing to the true heading to obtain
an LOP.
Flotilla 12-10
Navigation Study Guide
S6-5. How can a range be used to obtain an LOP if no
bearing was obtained for the range?
Extend the range until it crosses the course line. As
with any LOP, record the time the alignment
occurred on the top of the LOP
S6-6. A circle of position is based on a measurement of
distance to the charted object. What methods of measuring
distance are generally available to the navigator?
a. RADAR
b. Measurement of vertical angle with a sextant
c. Range Finder
Flotilla 12-10
Navigation Study Guide
S6- 7. When using the height of an object printed on the
l2l0-Tr chart, what are the units used and what is the
reference (datum) for the measurement?
feet; Mean High Water
S6-8. List six type of FIXES discussed in the text.
a. Cross Bearing; b. Range and Bearing;
c. Two Ranges; d. Two Distances;
e. Distance and Bearing of Object;
f. Passing close to a fixed Aid to Navigation.
Flotilla 12-10
Navigation Study Guide
S6-9. What factors can affect the accuracy of an LOP?
a.
b.
c.
d.
Inaccurate measurement of relative bearings
Mathematical Errors
Inaccurate Compass Readings
Inaccurate Plotting
S6-10. How are visual FIXES labeled?
A point with a full circle around it and the time
(in 24 hour format) parallel to the horizontal base
of the chart
Flotilla 12-10
Navigation Study Guide
S6-11. List the steps necessary to plot a running fix.
a. Allow for a time lapse between the 1st and 2nd bearing
b. One LOP is advanced by moving it parallel to itself in
the direction of the course line for the distance traveled.
The intersection of these two LOPs is the Running Fix.
c.
A new dead reckoning plot is started at the position of
the R FIX
d. Avoid advancing an LOP more than 30 minutes
End of Questions
Flotilla 12-10
Navigation Study Guide
PROBLEMS:
Use the 1210- Tr chart and the deviation table in Lesson 2.
P6-1. With the object dead ahead (RB 000°), plot and
label the following LOPs:
P6-1 OBJECT
TIME
BEARING
a. MONUMENT, CUTTYHUNK I. 6:13 p.m.
330
1813/330
b. CUPOLA, NAUSHON I.(NE)
9:30 a.m.
0930/000
012C
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Navigation Study Guide
P6-1 OBJECT
c. SPIRE, CHILMARK,
MARTHA'S VINEYARD
TIME
BEARING
1 :00 p.m.
314C
1300/298
d. SPIRE, GAY HEAD
MARTHA'S VINEYARD
10:53 p.m.
2253/150
168C
e. WATER TOWER
WOODS HOLE
10:16 a.m.
1016/140
157C
f. TOWER
GOOSEBERRY NECK
7:30 a.m.
0730/270
288C
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Navigation Study Guide
P6-1 OBJECT
g. TOWER
GOOSEBERRY NECK
TIME
BEARING
8:01 a.m.
358C
0801/345
h. BUTLER FLATS LIGHT
NEW BEDFORD
6:25 a.m.
0625/320
334C
i. NEW BEDFORD
R TR (WNBH)
6:25 a.m.
0625/309
324C
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Navigation Study Guide
P6-1 OBJECT
j. TOWER, WEST ISLAND
TIME
BEARING
3:28 a.m.
288C
0328/270
k. SOUTH TIP, PENIKESE I.
2:31 p.m.
1431/030
039C
l. RADAR TOWER
midnight 12:00
0000/352
MARTHA'S VINEYARD
005C
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Navigation Study Guide
P6-2. Plot and label the following ranges:
P6-2 TIME
a. 2:15 a.m.
0215
OBJECT (A)
GAY HEAD, SPIRE
OBJECT (B)
GAY HEAD LIGHT
Alt Gp Fl (3)&(1) R 40 s
b. 2: 15 p.m.
MARTHA'S VINEYARD
1415
CHILMARK SPIRE RADAR TOWER
c. 3:12 p.m.
1512
MARTHA'S VINEYARD
LOOKOUT TOWER AERO Rot W & G
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Navigation Study Guide
P6-2 TIME
OBJECT (A)
OBJECT (B)
d. 12:23 a.m.
WOODS HOLE
0023DOME
WATER TOWER
e. 7:35 a.m.
0735
ROUND HILL POINT
WINDMILL
TANK
f. 8:35 p.m.
2035
NASHAWENA ISLAND
MONUMENT
HOUSE
g. 11 :23 a.m.
CUTTYHUNK ISLAND
MONUMENT
LOOKOUT TOWER
1123
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Navigation Study Guide
P6-2 TIME
OBJECT (A)
h. 6:28 p.m. CUTTYHUNK I.
1828 LOOKOUT TOWER
i. 9:13 a.m.
0913
OBJECT (B)
NASHAWENA I.
MONUMENT
MARTHA'S VINEYARD
MENEMSHAPOND
RADAR TOWER
ENTRANCE LIGHT
j. 10:17 p.m.
FALMOUTH
TOWER
2217
STACK
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Navigation Study Guide
P6-3. Plot and label the following Circles of Position:
OBJECT
TIME
DISTANCE(M)
2215
a. GAY HEAD
10:15 p.m.
3.1
D 3.1
Alt Gp PI (3) W & (1) R
40 Sec 170 ft 17 M
D3.7
b. CUTTYHUNK ISLAND 7:15a.m.
LOOKOUT TOWER
2.0
0715
D 2.0
c. MARTHA'S VINEYARD 6:25 a.m.
LOOKOUT TOWER
4.2
0625
D 4.2
Flotilla 12-10
Navigation Study Guide
OBJECT
TIME
DISTANCE(M)
d. GAY HEAD SPIRE
8:25 a.m.
6.5 0825
D 6.5
e. MARTHA'S VINEYARD
AERO Rot W & G
2:28 p.m.
5.0
1428
D 5.0
f. NOMANS LAND
NORTH TIP
11 :38 p.m.
5.2
2338
D 5.2
g. PENIKESE I.
SOUTH TIP
12:03 a.m.
3.2
0003
D 3.2
Flotilla 12-10
Navigation Study Guide
OBJECT
h. WOODS HOLE
WATER TOWER
TIME
i. BUTLER FLATS LIGHT
DISTANCE(M)
3:15 p.m.
2.6 1515
D 2.6
6:18 p.m.
1.8
1818
D 1.8
D3.7
j. GOOSEBERRY NECK
TOWER
5:27 p.m.
1.9
1727
D 1.9
k.
1:00 p.m.
3.7
1300
D3.7
BUZZARD'S LIGHT
PI 2.5sec 101ft 22M HORN
Flotilla 12-10
Navigation Study Guide
P6-4. At 10:30 p.m., while on a course of C231 at 10.0 kn,
from Buoy "27" FIG 4 sec BELL, in Vineyard Sound, you
note a light flashing every six seconds on the starboard beam
(090R) when your heading is 251C.
a. Draw the course line and label it: C231
S10.0
b. Plot the bearing and label it:
2230
321
Flotilla 12-10
Navigation Study Guide
P6-5. While heading 251C, at 7:00 p.m. south of
PASQUE Island, you note a flashing green light every
four seconds off your port bow (315R). Plot the
1900
bearing and label it.
186
Flotilla 12-10
Navigation Study Guide
P6-6. The MONUMENT on NASHAWENA ISLAND
can be seen off the starboard bow (045R) while on
heading 25lC at 9:30 a.m.
Plot the bearing and label it. 0930
276
Flotilla 12-10
Navigation Study Guide
6-7 . On another day at 6:25 a.m., while running C262C at S
10.0, you sight the CUTTYHUNK ISLAND MONUMENT
on the starboard beam over the vessel's compass at 090R. At
the same time you note that the MONUMENT and the
HOUSE on NASHA WENA ISLAND are in range.
a. What is the compass bearing of the CUTTYHUNK
MONUMENT?352C
b. Plot and label the FIX, and determine its latitude and
longitude: DOT WITHIN CIRCLE, 0625
L: 41° 22.8'N Lo: 70° 55.4W
Flotilla 12-10
Navigation Study Guide
6-8. Southeast of GAY HEAD on MARTHA'S VINEYARD at
1527, you are barely making way, and you take a bow bearing
of 322C on GAY HEAD SPIRE. You then turn the boat
toward the AERO Rot W & G beacon at the airport on
MARTHA'S VINEYARD and obtain a bearing of 029C.
a. Plot and label these two LOPs and the resulting FIX:
1527 1527 DOT WITHIN CIRCLE, 1527
307
019
b. What is the position of the FIX?
L: 41° 15.7'NLo: 70° 40.4'W
Flotilla 12-10
Navigation Study Guide
6-9. At 0625 you are between NASHAWENA ISLAND and
GAY HEAD and note that the MONU- MENT and HOUSE
on NASHAWENA ISLAND are in range. You also note that
the SPIRE and the light on GAY HEAD (Alt Gp PI (3) W &
(1) R 40 sec, 170 ft 17 M) are in range. Plot these two LOPs
and plot and label the FIX they form.
FIX label: DOT WITHIN CIRCLE, 0625
What is the position of the FIX?
L: 41° 22.8'N Lo: 70° 55.4'W
Flotilla 12-10
Navigation Study Guide
6-10. At 0715, while on course ofC288C at ordered speed of
10.0 to, you detect a strong PIP on the RADAR at the NW tip
of GAY HEAD, range 5.6M. You also notice a good PIP about
the center of CUTTYHUNK ISLAND which you decide is the
TOWER and measure the range at 5.1M.
Plot and label these two LOPs and the FIX they determine.
a. FIX label: DOT WITHIN CIRCLE, 0715 RADAR
b. Position: L: 41° 20.3'N Lo: 70° 57.5'W
c. Bearing to PIP on GAY HEAD: 083
d. Bearing to PIP on CUTTYHUNK: 012
Flotilla 12-10
Navigation Study Guide
P6-11. While underway at 2215 on course C239C, you take a
RADAR distance (5.1M) and bearing (082R) on the North tip
of NOMANS LAND. Plot and label the LOPs, determine and
label the FIX, and provide its position.
a. FIX label:
DOT WITHIN CIRCLE, 2215 RADAR
b. Position:
c. Range LOP:
L: 41°13.2'N Lo: 70° 043.2'W
2215, 5.1
d. Bearing LOP: 2215, 302
Flotilla 12-10
Navigation Study Guide
P6-12. While underway on C23l/Sl0.0 from Buoy "27" PI G 4
sec BELL, approximately three miles southwest of WOODS
HOLE entrance in VINEYARD SOUND, you take a bearing
on the light at the head of TARPAULIN COVE, NAUSHON
ISLAND, PI 6 sec 78 ft 9 M, at bearing 090R at 5: 15 p.m. At
5:33 p.m. you take a bearing on the light at GAY HEAD, Nt
Gp PI (3) W & (1) R 40 sec, bearing 341R while on course.
a. Plot and label the course line:
C231
S10.0
b. Plot and label the 5:15 p.m. LOP: 1715
321
Flotilla 12-10
Navigation Study Guide
P6-12. (Continued)
c. Plot and label the 5:33 p.m. LOP:
C231
S10.0
d. Advance the 5: 15 LOP to 5:33.
Plot and label.
1715-1733
321
e. Plot and label the RUNNING FIX:
f. Position: L: 41° 24.7'N
1733 R FIX
Lo: 70° 47.0'W
Flotilla 12-10
Navigation Study Guide
P6-13. Assume all the same facts as in problem 6-12 with the
additional information that, over this time period, at 5:30 p.m.
a 2.5 kn current is flowing in VINEYARD SOUND toward
231 true.
a. Plot and label the course line:
C231
S10.0
b. Plot and label the 5: 15 p.m. LOP: 1715
321
Flotilla 12-10
Navigation Study Guide
P6-13. (Continued)
c. Plot and label the 5:33 p.m. LOP:
d. Advance the 5: 15 LOP to 5:33.
Plot and label.
e. Plot and label the RUNNING FIX:
f. Position:
1733
212
1715-1733
321
1733 R FIX
L: 41° 24.0'N Lo: 70° 47.6'W
Flotilla 12-10
Navigation Study Guide
P6-14. While underway on C251C/S 10.0 in VINEYARD
SOUND, you observe the light on GAY HEAD (Alt Gp PI (3)
W & (1) R 40 sec) bearing 3l5R at 10:30 a.m. Nine minutes
later the light is abeam (270R). Plot and label the RUNNING
FIX and determine its position.
1039 R FIX
L: 41° 22.1'N Lo: 70° 51.4'W
Flotilla 12-10
Navigation Study Guide
P6-15. Continuing from the position determined in 6-14
above, establish a danger bearing using BUZ- ZARDS LIGHT
(PI 2.5 sec 101 ft 22M HORN) to clear the Sow and Pigs Reef
by .5 M. What are the true, magnetic, and compass (ship's
head) danger bearings on the BUZZARDS LIGHT?
NLT 282T
NLT 297M
NLT 299C
Flotilla 12-10
Navigation Study Guide
P6-16. Departing at 6:11 p.m. from L: 41° l8.8'N Lo: 70°
5l.7'W, you are underway on C136C/S12.0. At 6:40 p.m. the
CHILMARK SPIRE on MARTHA'S VINEYARD is observed
to bear 236R while your heading is l36C.
a. Plot and label the course line:
C120
S12.0
b. Plot and label the 6:40 p.m. DR:
DOT WITHIN SEMICIRCLE and 1840 at angle
Flotilla 12-10
Navigation Study Guide
P6-16. (Continued)
1840
356
d. Plot and label an Estimated Position (EP) for the
6:40 p.m. LOP observation and determine its position:
DOT WITHIN SQUARE EP
L: 41° 15.9'N Lo: 70° 44.2'W
c. Plot and label the SPIRE LOP:
P6-17. Prove that an EP constructed from a DR position and
a single LOP is generally closer to the true position than the
DR position. See discussion in Study Guide
End of Problems